4-piperidone ketal derivatives,their preparation and their use as stabilizers

ABSTRACT

A SYNTHETIC POLYMER COMPOSITION STABILIZED AGAINST PHOTO- AND THERMAL-DETERIORATION IS DISCLOSED. THE STABILIZATION IS EFFECTED BY INCORPORATION IN THE COMPOSITION AN EFFECTIVE AMOUNT OF CERTAIN 4-PIPERIDONE KETAL DERIVATIVES.

3,790,525 4-PIPER1DONE KETAL DERIVATIVES, THEIR PREPARATION AND THEIRUSE AS STABILIZERS Keisuke Murayama, Toshimasa Toda, Eiko Mori, KatsuakiMatsui, Tomoyuki Kurumada, Noriyuki Ohta, and Ichiro Watanabe, Tokyo,Japan, assignors to Sankyo Company Limited No Drawing. Filed Jan. 19,1972, Ser. No. 219,133 Int. Cl. C08f 45/60; C08g 51/60 US. Cl. 260--45.8NZ 7 Claims ABSTRACT OF THE DISCLOSURE A synthetic polymer compositionstabilized against photoand thermal-deterioration is disclosed. Thestabilization is efiected by incorporating in the composition aneffective amount of certain 4-piperidone ketal derivatives.

SUMMARY OF THE INVENTION This invention relates to new 4-piperidoneketal derivatives, their preparation and their use as stabilizers.

More particularly, this invention is concerned with the 4-piperidoneketal derivatives having the formulae R 1 O R1 H3 C CH;

H80 N OH;

H (I) and H C L CH: H O N on,

wherein R represents an alkyl group of 1 to 8 carbon atoms and Rrepresents an alkylene group of 2 or 3 carbon atoms or o-phenylenegroup, a process for the preparation of the 4-piperidone ketalderivatives (I) and (II) and stabilization of synthetic polymers againstphotoand thermal-deterioration thereof by having incorporated therein,in a sufficient amount to prevent said deterioration, at least one ofthe 4-piperidone ketal derivatives (1) and (II).

In the above Formulae I and II, R may be illustrated by methyl, ethyl,n-propyl, isopropyl, n-butyl, tert.butyl n-pentyl, isopentyl, hexyl,heptyl and octyl; and R may be illustrated by ethylene, trimethylene,propylene and o-phenylene.

The term synthetic polymer as used herein are intended to embracepolyolefins including homopolymers of olefins such as low-density andhigh-density polyethylene, polypropylene, polystyrene, polybutadiene,polyisoprene and the like, and copolymers of olefins with otherethylenically unsaturated monomers such as ethylene-propyl enecopolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer,styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymerand the like; polyvinyl chlorides and polyvinylidene chlorides includinghomopolymer of each of vinyl chloride and vinylidene chloride, vinylchloride-vinylidene chloride copolymer and copolymers of each of vinylchloride and vinylidene chloride with vinyl acetate or otherethylenically unsaturated monomers; polyacetals such as polyoxymethyleneand polyoxyethylene; polyesters such as polyethylene United StatesPatent 0 ice terephthalate; polyamides such as 6-nylon, 6,6-nylon and6,10-nylon; and polyurethanes.

Synthetic polymers have been widely utilized in the art, in view oftheir excellent properties, in various forms or shapes, for example,filament, fibre, yarn, film, sheet, other molded article, latex andfoam. However, these polymers have some drawbacks such as poor lightandheat-stabilities and the like. Stated illustratively, polyolefins andpolyurethane elastomers frequently tend to undergo severe deteriorationwhen exposed to light such as sunlight or ultraviolet ray, and polyvinylchloride and polyvinylidene chloride frequently tend to deteriorate andbecome colored by the action of light and heat together with eliminationof hydrogen chloride therefrom. Polyamides are also frequently subjectedto photo-deterioration. For the purpose of stabilizing these syntheticpolymers against such deterioration, there have heretofore been proposedin the art a number of stabilizers; for example, for polyolefins,benzotriazole compounds and benzophenone compounds; for polyurethanes,phenol compounds and benzophenone compounds; and for polyvinyl chlorideand polyvinylidine chloride, lead salts such as basic lead silicate andtribasic lead maleate, and organotin compounds such as dibutyltinlaurate and dibutyltin maleate.

Although such prior stabilizers are known to be considerablysatisfactory, there still remained some problems to be improved.

Thus, numerous attempts have been made in the art to find and developnew and more effective stabilizers.

As a result of our extensive studies, it has now been found that the new4-piperidone ketal derivatives (I) and (II) of this invention can besatisfactorily prepared and exhibit a high stabilizing effect againstphotoand thermaldeterioration of the synthetic polymers.

It is, accordingly, an object of this invention to provide nev; anduseful 4-piperidone ketal derivatives (I) and (II Another object is toprovide a process for the preparation of the valuable 4-piperidone ketalderivatives (I) and (II).

Still another object is to provide synthetic polymer compositionstabilized against the deterioration thereof by having incorporatedtherein a sufficient amount to prevent the deterioration of at least oneof the 4-piperidone ketal derivatives (I) and (II).

Other objects of this invention will become apparent to those skilled inthe art from the following description.

In one aspect of this invention, the 4-piperidone ketal derivatives (I)and (H) are all new substances unknown in the art.

Representative of the 4-piperidone ketal derivatives of the aboveFormulae I and II are as follows:

Compound No.: Chemical name 1 4,4diethoxy-2,2,6,6-tetramethylpiperidine.

2 4,4 di n-butoxy-2,2,6,6-tetramethylpiperdine.

3 4,4 di n-octoxy-2,2,6,6-tetramethylpiperidine.

4 1,4 dioxa 8 aza-7,7,9,9-tetramethylspiro[4.5]decane.

5 1,5 dioxa-9-aza-8,8,10,IO-tetrarnethylspiro [5.5] undecane.

6 4,4 (o phenylenedioxy)-2,2,6,6-tetramethylpiperidine.

In another aspect of this invention, the 4-piperidone ketal derivatives(I) and (II) of this invention can be easily prepared according to theprocess of this invention, the process of which comprises reacting2,2,6,6-tetramethyl-4-piperidone (frequently and hereinbelow referred toas triacetonamine) with a monohydric alcohol having the formula R -OHwherein R is as defined above or a dihydric alcohol or phenol having theformula.

wherein R is as defined above in the presence of an acid catalyst.

In carrying out the process of this invention, the reaction can besuitably effected by intimately contacting triacetonamine with themonohydric alcohol (III) or the dihydric alcohol (IV) in the presence ofthe acid catalyst and, advantageously, under reflux in the presence of asuitable organic solvent. As the solvent may be advantageously employedany of inert water-immiscible organic solvents that could not adverselyaffect the reaction, reactants and catalyst. Examples of the solventinclude aliphatic and aromatic hydrocarbons, e.g., n-hexane,cyclohexane, benzene, toluene and xylene.

The monohydric alcohol of the above Formula III which may be employed inthe reaction includes straight or branched monohydric alcohols, e.g.,methanol, ethanol, isopropanol and octanol. The dihydric alcohol orphenol of the above Formula IV which may be employed in the reactionincludes, e.g., ethylene glycol, propylene glycol, trimethylene glycoland catechol. The acid catalyst which may be employed in the reaction isany of those catalysts commonly utilized in a standard condensationreaction with elimination of water and includes mineral acids, e.g.,hydrochloric acid and polyphosphoric acid; and organic acids, e.g.,methanesulfom'c acid, benzensulfonic acid and p-toluenesulfonic acid,the organic acids being preferable.

As it is noted that the reaction of the present process be acondensation reaction accompanied with elimination of water, thereaction may be more smoothly and preferably effected with continuousremoval of the water that is being formed in situ during the reactionproceeding.

After completion of the reaction, the desired product may be readilyrecovered and purified in a conventional manner, for instance, by makingthe reaction mixture alkaline with an alkali hydroxide, separating anorganic layer followed by distillation under reduced pressure and, itnecessary, recrystallization.

In still another aspect of this invention, there is provided a syntheticpolymer composition stabilized against photoand thermal-deteriorationwhich contains at least one of the new 4-piperidone ketal derivatives(I) and (II) having incorporated therein.

The 4-piperid0ne ketal derivatives (I) and (II) employed as a stabilizerin the present invention may be readily incorporated into the syntheticpolymer by any of the various standard procedures commonly utilized inthe art. The stabilizer may be incorporated into the synthetic polymersat any desired stage prior to the manufacture of shaped articlestherefrom. Thus, for example, the stabilizer in the form of a dry powdermay be admixed with the synthetic polymer, or a suspension or emulsionof the stabilizer may be admixed with a solution, suspension or emulsionof the synthetic polymer.

The amount of the 4-piperidone ketal derivatives (I) and (H) employed inthe synthetic polymer in accordance with the present invention may bevaried widely, depending upon the types, properties and particular usesof the synthetic polymer to be stabilized. In general, the 4-piperidoneketal derivatives of the Formulae I and II may be added in an amountranging from 0.01 to 5.0% by weight, based on the amount of thesynthetic polymer, but the practical range is varied depending upon thetype of the synthetic polymer, that is 0.01 to 2.0% by weight,preferably 0.02 to 1.0% by weight for polyolefins, 0.01 to 1.0% byweight, preferably 0.02 to 0.5% by weight for polyvinyl chloride andpolyvinylidene chloride, and 0.01 to 5.0% by weight, preferably 0.02 to2.0% by weight for polyurethanes and polyamides.

The present stabilizer may be used alone or in combination with otherknown antioxidants, ultraviolet absorbents, fillers, pigments and thelike.

If desired, two or more of the present stabilizers i.e. the 4-piperidoneketal derivatives of the Formulae I and II may also be satisfactorilyused in this invention.

In order that the invention may be better understood, the followingexamples are given solely for the purpose of illustration of thisinvention. In the examples, all parts are given by weight unlessotherwise indicated and the number of the test compound as usedhereinbelow is the same as illustratively shown above.

Examples 1 through 4 describe the preparation of the 4- piperidone ketalderivatives.

Examples 5 through 9 describe the synthetic polymer compositions havingincorporated therein the 4-piperidone ketal derivatives and theirstabilization efiects.

Example 1.4,4-di-n-butoxy-2,2,6,6-tetramethylpiperidine In a solution of23.4 g. of triacetonamine in ml. of benzene were added 23.2 g. ofn-butanol and 30 g. of ptoluenesulfonic acid. The resulting mixture washeated under reflux for 44 hours by means of a water separator.

Then, the reaction mixture was poured into a cold aqueous solution ofsodium hydroxide and the benzene layer was separated therefrom. Thelayer so separated was washed with water, dried over anhydrous sodiumsulfate and subjected to distillation under reduced pressure to give thedesired product as colorless liquids boiling at 123-124 C./4 mm. Hg.

IR (liquid film) v 1093, 1037 cm- Analysis.Calcd. for C H NO (percent):C, 71.52; H, 12.36; N, 4.91. Found (percent): C, 71.35; H, 12.44; N,5.14.

Example 2.4,4-di-n-octoxy2,2,6,6-tetramethylpiperidine The substantiallysame procedure as shown in the above Example 1 was repeated except thatn-octanol was employed instead of the n-butanol, thereby yielding thedesired product as colorless liquids boiling at 162 C./ 0.45 mm. Hg.

IR (liquid film) v 1092, 1038 cur- Analysis.--Calcd. for C H NO(percent): C, 78.67; H, 13.47; N, 3.67. Found (percent): C, 78.41; H,13.15; N, 3.85.

Example 3.-1,4-dioxa-8-aza-7,7,9,9-tetramethyl-spiro [4.5] decane Into asolution of 23.4 g. of triacetonamine in 150 ml. of benzene were added83 g. of ethylene glycol and 30 g. of p-toluenesulfonic acid and theresulting mixture was heated under reflux for 18 hours by means of awater Separator.

Then, the reaction mixture was treated in the same manner as shown inthe above Example 1 to give the desired product as colorless liquidsboiling at 103.5- 104.5 C./3.4 mm. Hg.

IR (liquid film) v 1091, 1040 cm" Analysis.-Calcd. for C H NO (percent):C, 66.29; I13, 109.62; N, 7.03. Found (percent): C, 66.39; H, 10.74;

Molecular weight (Osmometer): Calculated, 119.29; found, 205.7.

Example 4.4,4-(o-phenylenedioxy)-2,2,6,6-tetran1ethylpiperidine Thesubstantially same procedure as shown in the above Example 3 wasrepeated except that catechol was employed instead of the ethyleneglycol to give the desired product as colorless liquids boiling at118-120 C./3 mm. Hg.

Upon being allowed to cool, the liquids solidified and recrystallizationfrom aqueous methanol gave white crystals melting at 74-75 C.

IR (Nujol mull) v 1098, 1064 cm- Out-of-plane deformation absorption ofthe o-disubstituted benzene ring: 730-800 cmr Analysis.-Calcd. for C HNO (percent): C, 72.84; H, 8.56; N, 5.66. Found (percent): C, 72.73; H,8.71; N, 5.90.

Example 5 Into 100 parts of polypropylene (Noblen JHH-G, trade name,available from Mitsui Toatsu Chemicals Inc., Japan, employed after twicerecrystallizations from monochlorobenzene) was incorporated 0.25 part ofeach of the test compounds of this invention indicated below. Theresulting mixture was mixed and melted and then molded into a sheethaving a thicknessof 0.5 mm. under heating and pressure.

As a control for comparative purpose, the polypropylene sheet wasprepared in a similar manner to that described above without any ofstabilizers.

Then, all of these sheets thus formed were tested for the brittlenesstime (which means the time, expressed in terms of hour, until the testsheet becomes brittle) under ultraviolet ray irradiation at atemperature of 45 C. by means of the fade meter prescribed in JapaneseIndustrial Standard JIS-1044 entitled Testing Method of Color Fastnessto Light of Dyed Textiles and Dyestuffs, paragraph 3.8 (in English).

The results are given in the following Table 1.

TABLE 1 Test Compound No. Brittleness time (hours) 2 620 3 860 4 960None 100 Example 6 Into 100 parts of high-density polyethylene (Hi-Zex,trade name, available from Mitsui Toatsu Chemicals Inc., Japan, employedafter twice recrystallization from toluol) was incorporated 0.25 part ofeach of the test compounds of this invention indicated below. Theresulting mixture was made into a sheet having a thickness of 0.5 mm. bythe same procedure as in the above Example 5.

The sheet thus formed was tested for the brittleness time by the sametest method as in the above Example 5.

The results are given in the following Table 2.

TABLE 2 Test Compound No. Brittleness time (hours) 2 1400 4 1580 6 1920None 400 Example 7 method.

AGING TEST 1) Exposure to ultraviolet ray for 300 hours in the fademeter described above at 45 C.

(2) Aging at 160 C. for 2 hours in a Geers aging tester prescribed inJapanese Industrial Standard JIS-K-6301 entitled Physical TestingMethods for Vulcanized Rubber, Paragraph 6.5 (in English).

Into 100 parts of polyurethane prepared from polycaprolactone (E-5080,trade name, available from The Nippon Elastollan Industries Ltd., Japan)was incorporated 0.5 part of each of the test compounds of thisinvention indicated below. The resulting mixture was heated and meltedand then molded into a sheet having a thickness of about 0.5 mm. Thesheet thus formed was subjected to the exposure to ultraviolet ray for15 hours in the fade meter as specified in the above Example 5 at 45 C.and then tested for the retentions of elongation and tensile strength asin the above Example 7.

The results are given in the following Table 4.

TABLE 4 Retention Retention of elongaof tensile tion strength (percent)(percent) Test Compound No.:

2 92 4 88 89 6 94 None 75 53 Example 9 AGING TEST 1) Exposure for 600hours to the sunshine carbon apparatus prescribed in Japanese IndustrialStandard JIS Z-0230 entitled Accelerated Weathering Test of RustProofing Oils, paragraph 2.

(2) The sheet was aged for 90 minutes at C. in the Geers aging testerprescribed in the above Example 7. The results are given in thefollowing Table 5.

TABLE 5 Dlscoloration Sunshine carbon Geers aging tester apparatus(after 90 minutes,

(after 600 hours) 170 0.)

Test Compound No.:

2. Pale yellow Yellow.

g yyeowis t eowls. None Dark brown Blgck y From the above results it canbe seen that the 4-piperidone ketal derivatives of this inventionexhibit a high degree of stabilizing effect on synthetic polymersagainst deteriorations thereof.

What is claimed is: 1. A synthetic polymer composition stabilizedagainst photoand thermal-deterioration, said synthetic polymer 7 being apolyolefin, a polyvinylchloride, a polyvinylidene chloride, apolyacetal, a linear polyester, 2. polyamide having recurring amidegroups as integral parts of the polymer chain or a polyurethane, whereinthere is incorporated, in a suflicient amount to prevent saiddeterioration, a 4-piperidone ketal derivative having the formula HaCCH:

wherein R represents an alkylene group of 2 or 3 carbon atoms oro-phenylene group.

2. The synthetic polymer composition according to claim 1 wherein said4-piperidone ketal derivative is incorporated in an amount of Mil-5.0%by weight, based upon the amount of the synthetic polymer.

3. The synthetic polymer composition according to claim 1 wherein saidpolymer is a polyolefin.

4. The synthetic polymer composition according to claim 1 wherein saidpolymer is a polyvinyl chloride.

5. The synthetic polymer composition according to claim 1 wherein saidpolymer is a polyurethane.

6. The synthetic polymer composition according to claim 1 wherein saidpolymer is a polyamide having re- References Cited UNITED STATES PATENTS3,244,720 4/1966 Meschino 260-279 3,513,170 5/1970 Murayama et a1.260294.7 3,534,048 10/ 1970 Murayama et a1. 260-293 3,640,928 2/ 1972Murayama et a1. 260-23 3,692,778 9/1972 Murayama et a1. 260293.66

OTHER REFERENCES Noller, Chemistry of Organic Compounds, 1957, p. 204.

Stach et al., Chem. Abs, vol. 59, 87500.

DONALD E. OZAJA, Primary Examiner R. A. WHITE, Assistant Examiner U.S.Cl. X.R. 260 .8 N

